drivers/rtc/rtc-x1205.c

   1 /*
   2  * An i2c driver for the Xicor/Intersil X1205 RTC
   3  * Copyright 2004 Karen Spearel
   4  * Copyright 2005 Alessandro Zummo
   5  *
   6  * please send all reports to:
   7  *      Karen Spearel <kas111 at gmail dot com>
   8  *      Alessandro Zummo <a.zummo@towertech.it>
   9  *
  10  * based on a lot of other RTC drivers.
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/i2c.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc.h>
  20 #include <linux/delay.h>
  21
  22 #define DRV_VERSION "1.0.7"
  23
  24 /* Addresses to scan: none. This chip is located at
  25  * 0x6f and uses a two bytes register addressing.
  26  * Two bytes need to be written to read a single register,
  27  * while most other chips just require one and take the second
  28  * one as the data to be written. To prevent corrupting
  29  * unknown chips, the user must explicitely set the probe parameter.
  30  */
  31
  32 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
  33
  34 /* Insmod parameters */
  35 I2C_CLIENT_INSMOD;
  36
  37 /* offsets into CCR area */
  38
  39 #define CCR_SEC                 0
  40 #define CCR_MIN                 1
  41 #define CCR_HOUR                2
  42 #define CCR_MDAY                3
  43 #define CCR_MONTH               4
  44 #define CCR_YEAR                5
  45 #define CCR_WDAY                6
  46 #define CCR_Y2K                 7
  47
  48 #define X1205_REG_SR            0x3F    /* status register */
  49 #define X1205_REG_Y2K           0x37
  50 #define X1205_REG_DW            0x36
  51 #define X1205_REG_YR            0x35
  52 #define X1205_REG_MO            0x34
  53 #define X1205_REG_DT            0x33
  54 #define X1205_REG_HR            0x32
  55 #define X1205_REG_MN            0x31
  56 #define X1205_REG_SC            0x30
  57 #define X1205_REG_DTR           0x13
  58 #define X1205_REG_ATR           0x12
  59 #define X1205_REG_INT           0x11
  60 #define X1205_REG_0             0x10
  61 #define X1205_REG_Y2K1          0x0F
  62 #define X1205_REG_DWA1          0x0E
  63 #define X1205_REG_YRA1          0x0D
  64 #define X1205_REG_MOA1          0x0C
  65 #define X1205_REG_DTA1          0x0B
  66 #define X1205_REG_HRA1          0x0A
  67 #define X1205_REG_MNA1          0x09
  68 #define X1205_REG_SCA1          0x08
  69 #define X1205_REG_Y2K0          0x07
  70 #define X1205_REG_DWA0          0x06
  71 #define X1205_REG_YRA0          0x05
  72 #define X1205_REG_MOA0          0x04
  73 #define X1205_REG_DTA0          0x03
  74 #define X1205_REG_HRA0          0x02
  75 #define X1205_REG_MNA0          0x01
  76 #define X1205_REG_SCA0          0x00
  77
  78 #define X1205_CCR_BASE          0x30    /* Base address of CCR */
  79 #define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
  80
  81 #define X1205_SR_RTCF           0x01    /* Clock failure */
  82 #define X1205_SR_WEL            0x02    /* Write Enable Latch */
  83 #define X1205_SR_RWEL           0x04    /* Register Write Enable */
  84
  85 #define X1205_DTR_DTR0          0x01
  86 #define X1205_DTR_DTR1          0x02
  87 #define X1205_DTR_DTR2          0x04
  88
  89 #define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
  90
  91 /* Prototypes */
  92 static int x1205_attach(struct i2c_adapter *adapter);
  93 static int x1205_detach(struct i2c_client *client);
  94 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
  95
  96 static struct i2c_driver x1205_driver = {
  97         .driver         = {
  98                 .name   = "x1205",
  99         },
 100         .id             = I2C_DRIVERID_X1205,
 101         .attach_adapter = &x1205_attach,
 102         .detach_client  = &x1205_detach,
 103 };
 104
 105 /*
 106  * In the routines that deal directly with the x1205 hardware, we use
 107  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
 108  * Epoch is initialized as 2000. Time is set to UTC.
 109  */
 110 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
 111                                 unsigned char reg_base)
 112 {
 113         unsigned char dt_addr[2] = { 0, reg_base };
 114
 115         unsigned char buf[8];
 116
 117         struct i2c_msg msgs[] = {
 118                 { client->addr, 0, 2, dt_addr },        /* setup read ptr */
 119                 { client->addr, I2C_M_RD, 8, buf },     /* read date */
 120         };
 121
 122         /* read date registers */
 123         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 124                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
 125                 return -EIO;
 126         }
 127
 128         dev_dbg(&client->dev,
 129                 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
 130                 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
 131                 __FUNCTION__,
 132                 buf[0], buf[1], buf[2], buf[3],
 133                 buf[4], buf[5], buf[6], buf[7]);
 134
 135         tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
 136         tm->tm_min = BCD2BIN(buf[CCR_MIN]);
 137         tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
 138         tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
 139         tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
 140         tm->tm_year = BCD2BIN(buf[CCR_YEAR])
 141                         + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
 142         tm->tm_wday = buf[CCR_WDAY];
 143
 144         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 145                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 146                 __FUNCTION__,
 147                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 148                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 149
 150         return 0;
 151 }
 152
 153 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
 154 {
 155         static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
 156
 157         struct i2c_msg msgs[] = {
 158                 { client->addr, 0, 2, sr_addr },        /* setup read ptr */
 159                 { client->addr, I2C_M_RD, 1, sr },      /* read status */
 160         };
 161
 162         /* read status register */
 163         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 164                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
 165                 return -EIO;
 166         }
 167
 168         return 0;
 169 }
 170
 171 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
 172                                 int datetoo, u8 reg_base)
 173 {
 174         int i, xfer;
 175         unsigned char buf[8];
 176
 177         static const unsigned char wel[3] = { 0, X1205_REG_SR,
 178                                                 X1205_SR_WEL };
 179
 180         static const unsigned char rwel[3] = { 0, X1205_REG_SR,
 181                                                 X1205_SR_WEL | X1205_SR_RWEL };
 182
 183         static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
 184
 185         dev_dbg(&client->dev,
 186                 "%s: secs=%d, mins=%d, hours=%d\n",
 187                 __FUNCTION__,
 188                 tm->tm_sec, tm->tm_min, tm->tm_hour);
 189
 190         buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
 191         buf[CCR_MIN] = BIN2BCD(tm->tm_min);
 192
 193         /* set hour and 24hr bit */
 194         buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
 195
 196         /* should we also set the date? */
 197         if (datetoo) {
 198                 dev_dbg(&client->dev,
 199                         "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
 200                         __FUNCTION__,
 201                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 202
 203                 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
 204
 205                 /* month, 1 - 12 */
 206                 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
 207
 208                 /* year, since the rtc epoch*/
 209                 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
 210                 buf[CCR_WDAY] = tm->tm_wday & 0x07;
 211                 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
 212         }
 213
 214         /* this sequence is required to unlock the chip */
 215         if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
 216                 dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
 217                 return -EIO;
 218         }
 219
 220         if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
 221                 dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
 222                 return -EIO;
 223         }
 224
 225         /* write register's data */
 226         for (i = 0; i < (datetoo ? 8 : 3); i++) {
 227                 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
 228
 229                 xfer = i2c_master_send(client, rdata, 3);
 230                 if (xfer != 3) {
 231                         dev_err(&client->dev,
 232                                 "%s: xfer=%d addr=%02x, data=%02x\n",
 233                                 __FUNCTION__,
 234                                  xfer, rdata[1], rdata[2]);
 235                         return -EIO;
 236                 }
 237         };
 238
 239         /* disable further writes */
 240         if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
 241                 dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
 242                 return -EIO;
 243         }
 244
 245         return 0;
 246 }
 247
 248 static int x1205_fix_osc(struct i2c_client *client)
 249 {
 250         int err;
 251         struct rtc_time tm;
 252
 253         tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
 254
 255         if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
 256                 dev_err(&client->dev,
 257                         "unable to restart the oscillator\n");
 258
 259         return err;
 260 }
 261
 262 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
 263 {
 264         unsigned char dtr;
 265         static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
 266
 267         struct i2c_msg msgs[] = {
 268                 { client->addr, 0, 2, dtr_addr },       /* setup read ptr */
 269                 { client->addr, I2C_M_RD, 1, &dtr },    /* read dtr */
 270         };
 271
 272         /* read dtr register */
 273         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 274                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
 275                 return -EIO;
 276         }
 277
 278         dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
 279
 280         *trim = 0;
 281
 282         if (dtr & X1205_DTR_DTR0)
 283                 *trim += 20;
 284
 285         if (dtr & X1205_DTR_DTR1)
 286                 *trim += 10;
 287
 288         if (dtr & X1205_DTR_DTR2)
 289                 *trim = -*trim;
 290
 291         return 0;
 292 }
 293
 294 static int x1205_get_atrim(struct i2c_client *client, int *trim)
 295 {
 296         s8 atr;
 297         static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
 298
 299         struct i2c_msg msgs[] = {
 300                 { client->addr, 0, 2, atr_addr },       /* setup read ptr */
 301                 { client->addr, I2C_M_RD, 1, &atr },    /* read atr */
 302         };
 303
 304         /* read atr register */
 305         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 306                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
 307                 return -EIO;
 308         }
 309
 310         dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
 311
 312         /* atr is a two's complement value on 6 bits,
 313          * perform sign extension. The formula is
 314          * Catr = (atr * 0.25pF) + 11.00pF.
 315          */
 316         if (atr & 0x20)
 317                 atr |= 0xC0;
 318
 319         dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
 320
 321         *trim = (atr * 250) + 11000;
 322
 323         dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
 324
 325         return 0;
 326 }
 327
 328 struct x1205_limit
 329 {
 330         unsigned char reg, mask, min, max;
 331 };
 332
 333 static int x1205_validate_client(struct i2c_client *client)
 334 {
 335         int i, xfer;
 336
 337         /* Probe array. We will read the register at the specified
 338          * address and check if the given bits are zero.
 339          */
 340         static const unsigned char probe_zero_pattern[] = {
 341                 /* register, mask */
 342                 X1205_REG_SR,   0x18,
 343                 X1205_REG_DTR,  0xF8,
 344                 X1205_REG_ATR,  0xC0,
 345                 X1205_REG_INT,  0x18,
 346                 X1205_REG_0,    0xFF,
 347         };
 348
 349         static const struct x1205_limit probe_limits_pattern[] = {
 350                 /* register, mask, min, max */
 351                 { X1205_REG_Y2K,        0xFF,   19,     20      },
 352                 { X1205_REG_DW,         0xFF,   0,      6       },
 353                 { X1205_REG_YR,         0xFF,   0,      99      },
 354                 { X1205_REG_MO,         0xFF,   0,      12      },
 355                 { X1205_REG_DT,         0xFF,   0,      31      },
 356                 { X1205_REG_HR,         0x7F,   0,      23      },
 357                 { X1205_REG_MN,         0xFF,   0,      59      },
 358                 { X1205_REG_SC,         0xFF,   0,      59      },
 359                 { X1205_REG_Y2K1,       0xFF,   19,     20      },
 360                 { X1205_REG_Y2K0,       0xFF,   19,     20      },
 361         };
 362
 363         /* check that registers have bits a 0 where expected */
 364         for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
 365                 unsigned char buf;
 366
 367                 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
 368
 369                 struct i2c_msg msgs[2] = {
 370                         { client->addr, 0, 2, addr },
 371                         { client->addr, I2C_M_RD, 1, &buf },
 372                 };
 373
 374                 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
 375                         dev_err(&client->adapter->dev,
 376                                 "%s: could not read register %x\n",
 377                                 __FUNCTION__, probe_zero_pattern[i]);
 378
 379                         return -EIO;
 380                 }
 381
 382                 if ((buf & probe_zero_pattern[i+1]) != 0) {
 383                         dev_err(&client->adapter->dev,
 384                                 "%s: register=%02x, zero pattern=%d, value=%x\n",
 385                                 __FUNCTION__, probe_zero_pattern[i], i, buf);
 386
 387                         return -ENODEV;
 388                 }
 389         }
 390
 391         /* check limits (only registers with bcd values) */
 392         for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
 393                 unsigned char reg, value;
 394
 395                 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
 396
 397                 struct i2c_msg msgs[2] = {
 398                         { client->addr, 0, 2, addr },
 399                         { client->addr, I2C_M_RD, 1, &reg },
 400                 };
 401
 402                 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
 403                         dev_err(&client->adapter->dev,
 404                                 "%s: could not read register %x\n",
 405                                 __FUNCTION__, probe_limits_pattern[i].reg);
 406
 407                         return -EIO;
 408                 }
 409
 410                 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
 411
 412                 if (value > probe_limits_pattern[i].max ||
 413                         value < probe_limits_pattern[i].min) {
 414                         dev_dbg(&client->adapter->dev,
 415                                 "%s: register=%x, lim pattern=%d, value=%d\n",
 416                                 __FUNCTION__, probe_limits_pattern[i].reg,
 417                                 i, value);
 418
 419                         return -ENODEV;
 420                 }
 421         }
 422
 423         return 0;
 424 }
 425
 426 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 427 {
 428         return x1205_get_datetime(to_i2c_client(dev),
 429                 &alrm->time, X1205_ALM0_BASE);
 430 }
 431
 432 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 433 {
 434         return x1205_set_datetime(to_i2c_client(dev),
 435                 &alrm->time, 1, X1205_ALM0_BASE);
 436 }
 437
 438 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
 439 {
 440         return x1205_get_datetime(to_i2c_client(dev),
 441                 tm, X1205_CCR_BASE);
 442 }
 443
 444 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
 445 {
 446         return x1205_set_datetime(to_i2c_client(dev),
 447                 tm, 1, X1205_CCR_BASE);
 448 }
 449
 450 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
 451 {
 452         int err, dtrim, atrim;
 453
 454         if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
 455                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
 456
 457         if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
 458                 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
 459                         atrim / 1000, atrim % 1000);
 460         return 0;
 461 }
 462
 463 static struct rtc_class_ops x1205_rtc_ops = {
 464         .proc           = x1205_rtc_proc,
 465         .read_time      = x1205_rtc_read_time,
 466         .set_time       = x1205_rtc_set_time,
 467         .read_alarm     = x1205_rtc_read_alarm,
 468         .set_alarm      = x1205_rtc_set_alarm,
 469 };
 470
 471 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
 472                                 struct device_attribute *attr, char *buf)
 473 {
 474         int err, atrim;
 475
 476         err = x1205_get_atrim(to_i2c_client(dev), &atrim);
 477         if (err)
 478                 return err;
 479
 480         return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
 481 }
 482 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
 483
 484 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
 485                                 struct device_attribute *attr, char *buf)
 486 {
 487         int err, dtrim;
 488
 489         err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
 490         if (err)
 491                 return err;
 492
 493         return sprintf(buf, "%d ppm\n", dtrim);
 494 }
 495 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
 496
 497 static int x1205_attach(struct i2c_adapter *adapter)
 498 {
 499         return i2c_probe(adapter, &addr_data, x1205_probe);
 500 }
 501
 502 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
 503 {
 504         int err = 0;
 505         unsigned char sr;
 506         struct i2c_client *client;
 507         struct rtc_device *rtc;
 508
 509         dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
 510
 511         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
 512                 err = -ENODEV;
 513                 goto exit;
 514         }
 515
 516         if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
 517                 err = -ENOMEM;
 518                 goto exit;
 519         }
 520
 521         /* I2C client */
 522         client->addr = address;
 523         client->driver = &x1205_driver;
 524         client->adapter = adapter;
 525
 526         strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);
 527
 528         /* Verify the chip is really an X1205 */
 529         if (kind < 0) {
 530                 if (x1205_validate_client(client) < 0) {
 531                         err = -ENODEV;
 532                         goto exit_kfree;
 533                 }
 534         }
 535
 536         /* Inform the i2c layer */
 537         if ((err = i2c_attach_client(client)))
 538                 goto exit_kfree;
 539
 540         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 541
 542         rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
 543                                 &x1205_rtc_ops, THIS_MODULE);
 544
 545         if (IS_ERR(rtc)) {
 546                 err = PTR_ERR(rtc);
 547                 goto exit_detach;
 548         }
 549
 550         i2c_set_clientdata(client, rtc);
 551
 552         /* Check for power failures and eventualy enable the osc */
 553         if ((err = x1205_get_status(client, &sr)) == 0) {
 554                 if (sr & X1205_SR_RTCF) {
 555                         dev_err(&client->dev,
 556                                 "power failure detected, "
 557                                 "please set the clock\n");
 558                         udelay(50);
 559                         x1205_fix_osc(client);
 560                 }
 561         }
 562         else
 563                 dev_err(&client->dev, "couldn't read status\n");
 564
 565         device_create_file(&client->dev, &dev_attr_atrim);
 566         device_create_file(&client->dev, &dev_attr_dtrim);
 567
 568         return 0;
 569
 570 exit_detach:
 571         i2c_detach_client(client);
 572
 573 exit_kfree:
 574         kfree(client);
 575
 576 exit:
 577         return err;
 578 }
 579
 580 static int x1205_detach(struct i2c_client *client)
 581 {
 582         int err;
 583         struct rtc_device *rtc = i2c_get_clientdata(client);
 584
 585         if (rtc)
 586                 rtc_device_unregister(rtc);
 587
 588         if ((err = i2c_detach_client(client)))
 589                 return err;
 590
 591         kfree(client);
 592
 593         return 0;
 594 }
 595
 596 static int __init x1205_init(void)
 597 {
 598         return i2c_add_driver(&x1205_driver);
 599 }
 600
 601 static void __exit x1205_exit(void)
 602 {
 603         i2c_del_driver(&x1205_driver);
 604 }
 605
 606 MODULE_AUTHOR(
 607         "Karen Spearel <kas111 at gmail dot com>, "
 608         "Alessandro Zummo <a.zummo@towertech.it>");
 609 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
 610 MODULE_LICENSE("GPL");
 611 MODULE_VERSION(DRV_VERSION);
 612
 613 module_init(x1205_init);
 614 module_exit(x1205_exit);